Lapidary device



Patented Feb. 20, 1951 UNITED STATES PATENT OFFICE I LAPIDARY DEVICE Dan OBrien, Los Angeles, Calif. Application May 23, 1949, Serial No. 94,791

1 Claim. 1

This invention relates to a lapidary device of the type adapted to position a gem or precious stone for grinding and polishing the facets thereof upon a rotary table.

In such work, it is desirable to have the selected number of facets which constitute a row, equally spaced thereabout, as well as to have the facets of a subsequent elevation or row uniformly staggered or laterally displaced in relation to the adjacent row. Accordingly, by my device this positioning is effected in a highly efiicient and automatic manner and with a minimum of manipulation as well as a simplicity of structure.

In addition, my arrangement of elements is such that one may return the gem to any previous position in order to rework any facet of any row without having to reset the device and hence Without possibility of misalignment which is generally inherent in resetting. Thus means are provided for presetting the device simultaneously for (1) a number of rows of facets, (2) the desired number of facets in a row, and (3) the angular deviation of the facets of one row from those of an adjacent row.

Other objects and advantages of the invention will be apparent from the following description and claim, the novelty consisting in the features of construction, combination of parts, the unique relations of the members and the relative proportioning, disposition, and operation thereof, all as more completely outlined herein and particularly pointed out in the appended claim.

In the drawings, which form part of the present specification:

Figure 1 is a side elevational view of my lapidary device in operating position for working one row of facets of a gem, with the corresponding positions of the device for two subsequent rows indicated in broken lines;

Figure 2 is a top view-of the left portion of the structure only, as seen along the section line 2-2 of Figure 1, the dop arm and connected parts being removed;

Figure 3 is a bottom plan view of the index plate and locking pin as viewed along the line 33 which sections the dop arm of Figure 1; and

Figure 4 is an elevational View of a gem, showing the arrangement of three rows of facets which can be ground and polished by my device.

As here illustrated my gem faceting device includes a conventional angularly positioned dop arm carrying a longitudinally adjustable dop stick [2 secured within the lower tubular end thereof by a set screw 14. The dop stick is adapted to have a gem I6 firmly attached to its lower extremity by wax, resin or the like so as to be positioned at a predetermined angle atop a generally horizontal, rotary grinding or polishing table l8, operated by an electric motorv (not shown). The dop'arm is :provided with a longitudinal guide line 26 so that a protractor placed atop the rotary table l8 may quickly indicate the angle of the dop arm and gem l6 thereto.

By the present construction, means are provided for setting the gem and dop arm at any three successive angles-corresponding to three rows of facetsby supporting the upper end of the dop arm at predetermined elevations or stops. The positions of elevation are arranged so that the dop arm can be changed from one to the other at will, without altering the setting of any of the adjustable supports so that the gem can be instantly shifted back to a facet of a previous row without requiring adjustment of the setting anew. Thus three rows of facets can be ground in turn on the rotary table and then the same successions of facets be brought back to the table for polishing.

For-this purpose there is provided a standard 22 consisting of a flat [base 24 having three upright posts 26, 28, 30 located thereon, laterally spaced apart, with the top of the post 26 turned in at right angles to form a supporting cross arm 32 for the upper end of the center post. The center post 28 is rotatable on its longitudinal axis by means of pintles 34, 36 inserted in corresponding sockets in the base 24 and cross arm 32 respectively. This post has a pair of collars 38, 46 individually slidable therealong and-capable of being secured against displacement by corresponding set screws 43, 44. Each collar has a laterally projecting finger 46, 48 formed integral therewith and provided withv amutually facing, side-opening notch 50, 52 positioned to engage the inner post 30 when rotated thereagainst.

The inner post 36 also carries a longitudinally displaceable collar 54 afiixed to an outwardly projecting bracket arm 56 which supports a horizontal pan or tray 58 having an upstanding peripheral shoulder 60 about its upper surface. Disposed beneath the collar 54 is a second collar 62 slidingly mounted on the post 30, each of which collars may be anchored along the post by a corresponding set screw 64, 66. The collar 54 is fastened to the post only while adjusting the other three positioning collars for the three desired elevations of the tray 60. In use, the screw 64 is loosened and the collar 54 allowed to rest upon the under collar 62 which is set at the position adapted to give the desired angle of the dop arm when supported by the tray 58. The collars 38 and 40 are set for successive positions of elevation, with their arms 46, 48 set to include a wide angle so that first one and then the other may be swung in, under the collar 54 to support it at a desired elevation corresponding to other rows of facets on the gem Hi.

There are further provided means for positioning the stone 16 for cutting or polishing a varied number of facets which. constitute a complete row This is achieved bya'fi'at, polygonal sided index plate 10 adapted to have the upper end 12 of the dop arm inserted thru a central aperture 14 thereof and in such position to be securely lodged against a boss 16 of the doparm by a helical spring 18 held in compression about the arm 10 by a locking collar 80'. The index plate is rotatable about the dop arm and i's restrained against same by means of a right-angle locking pin 82 carried by the boss 16 and having its turned-up end 84 received in a socket of the plate 18'. The kniveedge of the plate rests upon the tray 58 back of the annular: shoulder 68 atan angle dependent upon the elevation of the tray. However the whole unit of dop'arm' and assembled gem and index plate can be lifted oil the tray 58 at will and placed back' again to resume its original position. In addition, by turning the dop arm andindex plate-to-rest on successive side edges of the latter, the gem could beturned to the number of facets for each row (or-elevation), corresponding to the number of sides of the plate. Thus the index plate shown in- Figure 3 has eight sides, so that by its use eight facets can be located for any elevation of the plate 58 without changing the setting of the locking pin 82.

However means are also provided for faceting successiverows of thegem at planes'non -parallel or angularly displaced from the facets of; the pre ceding row; Such' angular" deviation represents an aliquot divisor of the radical sector 86 defined by each polygonal edge of" the index plate. Accordingly sockets 88 are placed in the plate 10' to receive the end 84 of the locking pin in positions corresponding to desired rotational positions of the doparm inrelation to theindex plate; Thus, assuming the socket 880 corresponds to the facets cof Figure 4; the socket 881) which bisects the sector 86 corresponds to the facets 6;

the sockets 88d correspond to the facets a: and

so on. An index plate having a different number of edges, e; g. 3; 4, 5, 6; etc. can likewise have its sectors divided up for such intermediatesockets. It will be seen likewise that as' soon as the locking pin 82' is located in the desired socket of any sector, the plate and dop arm can be. rested on successive polygonal edgesof the plate with,- out disturbing the setting: of the locking pin through a complete (360? rotation of the unit.

4 Here again, it will be evident that not only can an elevationor row of facetsbe returned to at will by means of the stops 38, 40, 62, but the device can be reset for any individual facet in any row by means of the sockets 88.

While I have shown and described in some detail a presently preferred embodiment of my gem faceting device, it is understood that various modifications may be made. in. the construction andbperationthereof within the spirit and scope of the subsequently claimed invention which it is; my intention to claim broadly within the limitations imposed by the prior art.

Iclaim:

A lapidary device of the character described, comprising in combination: a pair of upright post's laterally spaced apart, one of which carries'v a vertically adjustable horizontal support and an independently vertically adjustable positioning collar disposed beneath the support, the other of which posts is axially rotatablean'd carries. a pair of independently vertically adjustable collars axially spaced apart and each having a rigid lateral extension individually adapted alternately to support said horizontal support from beneath, whereby the three collars may be set to position the horizontal. support at three successive elevations; an elongated shaft one end of which. is adapted; to support a. gem on a rotatable grinding or polishing surface; a polygonal si'ded plate axially traversed by said shaft and rotate;- ble toselectedv stations thereabout, said plate being supportable along any one of its edges. by said horizontal support. and containing sockets at successive. positions which are divisions of the sector angle defined by consecutive ends of, a polygonal edge; a. projectionarm. carried by saidshaft andv insertable in successive sockets; and retaining meansdisposed in opposition to said armand adapted: normally to hold samev in its selected socket. DAN f OBRIEN.

REFERENCES CITED The following references are of record inthe file: of. this. patent UNITED STATES PATENTS Number Name- Date 893,920:- Griesch a July 21-, 1908 1 269302 Ries June'll 1918 1,284,109 Hunt Nov. 5,. 1918 OTHER REFERENCES Revised Lapidary Handbook? by J. Howand, published by J. H. Howard, 504, Crescent Avenue,,Greenville, S. C.,- 1946; pages 121 to 124 inclusive. 

